1. Technical Field
The present invention relates to a flow path member which has a filter that removes foreign matter which is included in liquid, an ink jet head which includes the flow path member, and an ink jet printer.
2. Related Art
The ink jet printer includes a permanent head, and is an apparatus which ejects (discharges) various liquids from the permanent head. The ink jet printer is a non-impact type printing apparatus, in which characters are formed by ejecting particles or droplets of ink onto a paper sheet (JIS X0012-1990). A dot printer that is a printer which prints a character or an image that is expressed at a plurality of points is one aspect, and prints the character or the image which is expressed by the plurality of points that are formed by ejection of particles or droplets of ink. In addition, the permanent head continuously or intermittently generates liquid droplets of ink, and is a machine section or electric section of a printer body (hereinafter referred to as an “ink jet head”) (JIS Z8123-1: 2013). In addition to being used as an image recording apparatus, the ink jet printer is also applied to various manufacturing apparatuses by taking advantage of the feature in which it is possible to accurately land a very small amount of liquid at a prescribed position. For example, the ink jet printer is applied to a display manufacturing apparatus which manufactures a color filter of a liquid crystal display or the like, an electrode forming apparatus which forms an electrode such as an organic EL (Electro Luminescence) display, an FED (Field Emission Display) or the like, and a chip manufacturing apparatus which manufactures a bio chip (bio-chemical element). Then, a recording head for the image recording apparatus ejects liquid ink, and a color ejecting head for the display manufacturing apparatus ejects each color liquid of R (red), G (green), and B (blue). In addition, an electrode material ejecting head for the electrode forming apparatus ejects electrode material in liquid form, and a bio-organic material ejecting head for the chip manufacturing apparatus ejects liquid bio-organic material.
The ink jet head above takes in ink from an ink cartridge into which ink that is one type of liquid is filled to a pressure chamber via a liquid flow path within a flow path member, and ejects ink droplets from a nozzle by generating pressure variation in ink within the pressure chamber by driving of a piezoelectric element (one type of actuator). In addition, the flow path member is known which includes a filter at the middle of a liquid flow path in order to remove bubbles, foreign matter, and the like which are included in ink (for example, refer to JP-A-2009-101578).
In such a flow path member which includes a filter, there are times when the filter changes shape at the downstream side due to pressure of flowing ink. In particular, it is easy for the filter to change shape at the downstream side in a case where liquid ink with a relatively high viscosity or the like passes through the filter. Then, when the filter changes shape at the downstream side and comes into contact with a wall surface of the liquid flow path at the downstream side, for example, a bottom surface of a filter chamber on which the filter is arranged or the like, the effective area of the filter is reduced and pressure loss is increased. Thereby, back pressure of the liquid flow path at the downstream side is reduced and there is a risk that a meniscus of ink which is formed in the nozzle is destroyed.